package testingtool;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;

public class HashSetTesting {

	public static void main(String[] args) {
		
		List<String> list1 = new ArrayList<String>();
		list1.add("a");
		list1.add("b");
		
		List<String> list2 = new ArrayList<String>();
		list2.add("b");
		list2.add("c");
		
		HashSet<String> hs = new HashSet<String>();
		hs.addAll(list1);
		hs.addAll(list2);
		
		
		System.out.println(hs.size());
		hs.add(null);
		System.out.println(hs.size());
		
	}

}
